5 books in series

National Geographic Readers: Level 3

National Geographic Readers: Level 3 is a 5-book series with 5 released primary works first released in 2011 with contributions by Elizabeth Carney, Melissa Stewart, Kitson Jazynka, Libby Romero, and Laura Marsh.

Great Migrations: Whales
National Geographic Readers: What Is an Archaeologist?
Robots
Mars
Sacagawea
Cats vs. Dogs